package com.margo.project.curator.counter;

import java.io.IOException;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.shared.SharedCount;
import org.apache.curator.framework.recipes.shared.SharedCountListener;
import org.apache.curator.framework.recipes.shared.SharedCountReader;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.retry.ExponentialBackoffRetry;

import com.google.common.collect.Lists;

/**
 * http://ifeve.com/zookeeper-sharedcount/
 * @author fangxingbang
 *
 */
public class SharedCounterExample implements SharedCountListener {
	private static final int QTY = 5;
	private static final String PATH = "/counter";

	public static void main(String[] args) throws IOException, Exception {
		final Random rand = new Random();
		SharedCounterExample example = new SharedCounterExample();

		CuratorFramework client = CuratorFrameworkFactory.newClient("localhost:2181",
				new ExponentialBackoffRetry(1000, 3));
		client.start();

		SharedCount baseCount = new SharedCount(client, PATH, 0);
		baseCount.addListener(example);
		baseCount.start();

		List<SharedCount> examples = Lists.newArrayList();
		ExecutorService service = Executors.newFixedThreadPool(QTY);
		for (int i = 0; i < QTY; ++i) {
			final SharedCount count = new SharedCount(client, PATH, 0);
			examples.add(count);
			Callable<Void> task = new Callable<Void>() {
				public Void call() throws Exception {
					count.start();
					Thread.sleep(rand.nextInt(10000));
					System.out.println("Increment:"
							+ count.trySetCount(count.getVersionedValue(), count.getCount() + rand.nextInt(10)));
					return null;
				}
			};
			service.submit(task);
		}

		service.shutdown();
		service.awaitTermination(10, TimeUnit.MINUTES);

		for (int i = 0; i < QTY; ++i) {
			examples.get(i).close();
		}
		baseCount.close();

	}

	public void stateChanged(CuratorFramework arg0, ConnectionState arg1) {
		System.out.println("State changed: " + arg1.toString());
	}

	public void countHasChanged(SharedCountReader sharedCount, int newCount) throws Exception {
		System.out.println("Counter's value is changed to " + newCount);
	}

}
